HVDC development started with the transmission of power in an order of magnitude of a few hundred MW and has continuously increased to large transmission ratings over long distances. By these developments, HVDC has become a mature and reliable technology with increasing power capacity that require systems capable of handling the increased power capacity.
A HVDC electric power distribution system uses direct current for the transmission of electrical power. HVDC transmission systems may be less expensive and may suffer lower electrical power losses over long-distance transmission. Generally, a HVDC transmission system comprises an overhead or cable transmission line and a terminal station. HVDC disconnectors may be used to connect and disconnect a transmission line from a terminal station.
In order to improve operating performance and to handle increased power capacity, there is a rising trend towards composite insulators instead of traditional glass and porcelain insulators. With composite insulators there is a greater need for the contacts to have larger contact areas and to have a greater ability to handle the increased power capacity. In addition separated contacts have an important role in view of the effect of pollution on the electrostatic field in HVDC systems.
Generally, knee-type disconnectors have one rotating and two fixed insulators. The knee-type HVDC disconnectors have a mobile arm that moves along a vertical plane. Thus, knee-type disconnectors enable distance between adjacent poles to be reduced in order to have a reduced overall space occupation. Knee-type disconnectors are preferred for use in HVDC transmission lines in view of the overall dimension.
The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of the prior art system.